Steam Family Sharing allows close friends and family members to play one another's games while earning their own Steam achievements and saving their own game progress to the Steam cloud. It's all enabled by authorizing a shared computer.

Sounds neat, but it does look convoluted and complex. I have a simpler system, which is quite revolutionary. It's called physical copies and I can just give them to friends. It's magic.

I don't know... Theoretically speaking, while RPGs, adventure games or other genres that have a story and an ending might be problematic, I think Minecraft and similar games are very much like physical games in this regard. As long as you don't log in and play the same time as your sister (is it even possible to do so?), it's the same as lending your brother one of your LEGO sets (or model airplanes, or whatnot). And nobody has ever wanted to outlaw that now, have they.

With a story-based game, the picture is not as clear: if you have already finished it, you've got everything that you wanted from it, so giving it to someone is kind of cheating, as if you could give a bottle of coke that you've drunk to someone, and they'd be able to drink it again, too.

Then again, books tend to go around like that, and nobody complains much about people lending books to one another, so I don't see why other sectors of the entertainment industry should be entitled to do so.

Finally, I believe that the (nuclear) family can well be considered one unit (it is, in many respects, by law), and I've never felt any scruples against sharing my stuff with my brother, or nowadays, with my wife. It would be completely insane if we had to buy every book, movie and CD twice...